Elkin, William Lewis
Elkin, William Lewis
positional astronomy, meteoritics.
At the time of Elkin’s birth his father, Lewis, was inspector of public schools for the city of New Orleans, but he later became a manufacturer of carpets and prospered financially. In 1867 he was appointed representative of the state of Louisiana at the forthcoming Parìs Exposition but died unexpectedly just before the family’s departure for Europe. All arrangements had been made and his widow. Jane Fitch Elkin, was persuaded to go as scheduled, taking with her their twelve-year-old son William, the only survivor of her five children. Mother and son became expatriates, leading an interesting but peripatetic life in various countries, so that Elkin’s secondary education was unorthodox. He did, however, attend private schools in Switzerland but at the age of fifteen had a serious illness, which left his health permanently impaired.
Nevertheless, Elkin decided upon a career as an engineer and enrolled in the Royal Polytechnic School at Stuttgart, from which he graduated in 1876 with a C.E. degree. But by now his interest had changed to astronomy; so he went to Strasbourg to study under Friedrich August Theodor Winnecke, then considered the foremost teacher of astronomy in Europe. He was a third-year graduate student, preparing a dissertation on the star α Centauri, when a chance meeting with David Gill, newly appointed royal astronomer at the Cape of Good Hope, led to an invitation to South Africa for a working (but personally financed) visit. After receiving his Ph.D. in 1880, Elkin joined Gill and his wife at the Cape and lived with them like a son for more than two years. Together Gill and Elkin set up and shared an ambitious observing program with a four–inch heliometer, to determine the parallaxes of nine stars: three observed by each separately and three by both of them. One of the latter was α Centauri, for which they published a value of 0.75″, with a probable error of 0.01″ (compared to today’s value of 0.760″ ± 0.005″).
Meanwhile, a six–inch heliometer had been installed in the Yale University Observatory, and Elkin was invited to come there, as “astronomer in charge of the heliometer.” He arrived in 1884 and remained in New Haven for the rest of his life, at first actively observing, then serving as director of the Yale observatory from 1896 (the year he married Catharine Adams) until increasing disability forced his retirement in 1910, at the age of fifty-five. The remaining twenty-three years of his life were spent as an invalid, with no further astronomical activities.
During his productive years at Yale, Elkin performed a formidable amount of work with the heliometer. The labor of measuring parallactic angles is great enough with today’s photographic techniques but was many times greater with the heliometer, which in addition was an exhausting instrument to use. Elkin, together with his students, used the Yale heliometer to determine the parallaxes of 238 stars; this was, in the words of Frank Schlesinger (Elkin’s successor at Yale), “by far the most important single contribution to our knowledge of stellar distances up to that time.”
Concurrently Elkin was cooperating with Gill in an attempt to get an improved value for the solar parallax, by making simultaneous observations, from their widely separated locations, of the minor planets Iris, Victoria, and Sappho. Other observatories with heliometers later joined in this program. Their value, published in 1896–1897, was 8.812″ ± 0.009″, close to the 8.790″ obtained in 1930–1931 with photographic techniques; however, both have now been superseded by a value of 8.79415″, derived from 1961 radar observations of the planet Venus.
Elkin also undertook a program for determining the positions of stars near the north celestial pole, at the request of E. C. Pickering (then director of the Harvard College Observatory), who needed good reference points for a projected photographic survey of that part of the sky. Elkin himself never used photography for determining stellar positions, although in papers published in 1889 and 1892 he compared photographic data on stars in the Pleiades cluster with his own heliometer measurements and declared that the new method showed promise. He did, however, apply photographic techniques to the study of meteors: using two “meteorographs,” each consisting of a number of cameras mounted on a motor–driven polar axis and placed several miles apart, he was able to determine the heights at which one Leonid meteor appeared and disappeared—many more were observed visually, but apparently his photographic emulsion was not fast enough to record them. Of greater significance was his use of a rotating bicycle wheel with occulting segments placed in front of his cameras to produce the first successful interrupted photographs of meteor trails, thereby providing information on their velocities.
Recognition for his work was international. Elkin was elected a foreign associate of the Royal Astronomical Society in 1892, received an honorary M.A from Yale in 1893, and became a member of the American Academy of Sciences in 1895. He shared with his student Frederick Lincoln Chase the Prix Lalande of the French Academy of Sciences in 1908 (for work on stellar parallaxes) and was awarded an honorary Ph.D. by the University of Christiania (now Oslo) in 1911.
I. Original Works. Elkin’s dissertation was published Parallaxe von α-Centauri (Karlsruhe, 1880). His work at the Cape observatory appeared as “I. Heliometer-Determinations of Stellar Parallax in the Southern Hemisphere,” in Memoirs of the Royal Astronomical Society, 48 (1884), 1–194, written with David Gill. His heliometer work at Yale was published under the general title “Researches With the Heliometer,” in Transactions of the Astronomical Observatory of Yale University, with those papers mentioned in the text being “Determination of the Relative Positions of the Principal Stars in the Group of the Pleiades,” 1 , pt. 1 (1887), 1–105; “Triangulation of Stars in the Vicinity of the North Pole,” 1 , pt. 3 (1893), 149–182; and “Catalogue of Yale Parallax Results,” 2 , pt. 4 (1912), 385–400, written with Frederick L. Chase and Mason F. Smith.
The solar parallax program is described in Annals of the Royal Observatory, Cape Town, 6 (1897) and 7 (1896), “planned and discussed by David Gill... with the cooperation of Arthur Auwers and W. L. Elkin”; “Discussion of the Observations of Iris,” 6 , pt. 4 (1)–(169), is the only part signed by Elkin.
Elkin’s critiques of photographic methods were “Comparison of Dr. Gould’s Reductions of Mr. Rutherfurd’s Pleiades Photographs With the Heliometer-Results,” in Astronomical Journal, 9 (1889), 33–35; and “The Rutherfurd Photographic Measures of the Pleiades,” in Publications of the Astronomical Society of the Pacific, 4 (1892), 134–138.
Elkin published only four brief papers on meteors (but see paper by Olivier listed below): “Photography of Meteors,” in Astronomical Journal, 13 (1893), 132; “Photographic Observations of the Leonids at the Yale Observatory,” in Astrophysical Journal, 9 (1899), 20–22; “Results of the Photographic Observations of the Leonids, November 14–15, 1898,” ibid., 10 (1899), 25–28; and “The Velocity of Meteors as Deduced From Photographs at the Yale Observatory,” ibid., 12 (1900), 4–7.
A list of thirty-one publications by Elkin appears in Frank Schlesinger’s biographical memoir (see below).
II. Secondary Literature. Gill’s account of his first encounter with Elkin and their subsequent association at the Cape observatory constitutes the preface to their joint article in Memoirs of the Royal Astronomical Society (see above). Further facts about Elkin appear in Monthly Notices of the Royal Astronomical Society, 94 (1934), 285–289, with photograph (written by H. Spencer Jones, then astronomer royal); and in Frank Schlesinger, Biographical Memoirs. National Academy of Sciences, 18 (1938), 175–188, with portrait and list of publications. Elkin is listed in Who Was Who in America, I (Chicago, 1943), 365.
An account of the awarding of the Prix Lalande for 1908 occurs in Comptes rendus hebdomadaires des séances de l’Académie des sciences, 147 (1908), 1123. Elkin’s unpublished work on meteors was presented and analyzed by Charles P. Olivier as “Results of the Yale Photographic Meteor Work, 1893–1909,” in Astronomical Journal, 46 (1937–1938), 41–57.
Sally H. Dieke